Strange medal -- struck on fused metal powder?
jonathanb
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This medal has the design of HK-701, but is in an unlisted white-colored metal (HK-701 is listed as bronze). It's a fairly rare piece and So-Called Dollar collectors might enjoy seeing it, but that's not actually the reason I'm posting.
The edge of the medal has a very odd appearance, and that is the reason I'm posting. It looks like the medal is composed of many small metallic grains, all fused together. The grains are pretty uniform in size, and if the medal is about 2.6 mm in thickness according to my cheap calipers, that puts the grains at about 250 microns in diameter. Judging by appearance, I would guess the medal is copper-nickel. It is non-magnetic, 38.2 mm and weighs 18.2 grams.
Another specimen appeared in the Weber sale a couple of months ago (lot 10530), where it was described this way:
<< <i>Same die pairs as HK 701 but struck in heavy white metal. Careful examination reveals the same die letter punches as used on the HK 680-687 Santa Monica Breakwater pieces. Brilliant Uncirculated. Edge has unusual small dots pattern. CENTENNIAL DAYS 1949 SHOOTING LYNCHIN HANGIN on the obverse, six sided star at bottom. LONG BEACH CENTENNIAL DAYS RIP-ROARING DAYS OF THE WEST on the reverse. The only piece graded by NGC, this piece is graded MS61. Unlisted and previously unknown in White Metal, 38.3 mm, 275.5 grains. >>
...and that specimen was clearly struck from the same dies as mine (see die polish mark extending downward from corner of L in LONG BEACH). As with mine, they note an "unusual small dots pattern" on the edge. FWIW, I see no sign of the small dots pattern on the struck face of the obverse or reverse.
So the question at hand is: What's the deal?
I can imagine striking a medal on power that becomes fused by the force of the strike. It seems like that would be incredibly messy, though, and hardly practical.
I can also imagine a collar that had little craters etched into it, resulting in the appearance of grains when the medal was struck. We're talking very small details though, and the ridges between the craters would be very small. I'd expect them to be worn off the collar more or less immediately by the shearing force of ejecting the medal after each strike. Also, the grain-like pattern does appear to extend into the "bevel" between the edge and the rim, which I don't think would be in direct contact with a collar die.
That said, since we know that there are at least two pieces with similar characteristics, the grainy appearance must be a result of something consistent in the production process.
Can anyone figure out what caused this?
The edge of the medal has a very odd appearance, and that is the reason I'm posting. It looks like the medal is composed of many small metallic grains, all fused together. The grains are pretty uniform in size, and if the medal is about 2.6 mm in thickness according to my cheap calipers, that puts the grains at about 250 microns in diameter. Judging by appearance, I would guess the medal is copper-nickel. It is non-magnetic, 38.2 mm and weighs 18.2 grams.
Another specimen appeared in the Weber sale a couple of months ago (lot 10530), where it was described this way:
<< <i>Same die pairs as HK 701 but struck in heavy white metal. Careful examination reveals the same die letter punches as used on the HK 680-687 Santa Monica Breakwater pieces. Brilliant Uncirculated. Edge has unusual small dots pattern. CENTENNIAL DAYS 1949 SHOOTING LYNCHIN HANGIN on the obverse, six sided star at bottom. LONG BEACH CENTENNIAL DAYS RIP-ROARING DAYS OF THE WEST on the reverse. The only piece graded by NGC, this piece is graded MS61. Unlisted and previously unknown in White Metal, 38.3 mm, 275.5 grains. >>
...and that specimen was clearly struck from the same dies as mine (see die polish mark extending downward from corner of L in LONG BEACH). As with mine, they note an "unusual small dots pattern" on the edge. FWIW, I see no sign of the small dots pattern on the struck face of the obverse or reverse.
So the question at hand is: What's the deal?
I can imagine striking a medal on power that becomes fused by the force of the strike. It seems like that would be incredibly messy, though, and hardly practical.
I can also imagine a collar that had little craters etched into it, resulting in the appearance of grains when the medal was struck. We're talking very small details though, and the ridges between the craters would be very small. I'd expect them to be worn off the collar more or less immediately by the shearing force of ejecting the medal after each strike. Also, the grain-like pattern does appear to extend into the "bevel" between the edge and the rim, which I don't think would be in direct contact with a collar die.
That said, since we know that there are at least two pieces with similar characteristics, the grainy appearance must be a result of something consistent in the production process.
Can anyone figure out what caused this?
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it's a Centennial (100 yr anniv) medal.......reminiscing the "good old days" apparently
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Another poster suggested lead shot, and it could have been struck from compressed tin or other metal shot (but not lead alone - lead would not stay bright that long). [Shot poured into a closed face & edge die, then struck with a face die?? Naw -- too hard to get out of the contraption. Maybe it's compressed bleu cheese and the edge shows the mould veins..??.]
Actually, the edge looks like those squished popcorn cakes or rice cakes sold as snacks in stores.
"A dog breaks your heart only one time and that is when they pass on". Unknown
Is that how they grow hypoallergenic beef?
"A dog breaks your heart only one time and that is when they pass on". Unknown
The grain size is determined by the fineness of the powder that you started with. In this particular case, they control the fineness of the powder and the sintering process in order to get a metal with lots of voids in it to hold lubrication.
This sure looks like bearing style sintered bronze to me. Please provide an alternate explanation for the interesting photo in the OP! Partially fused blobs is what i'd call it.
[edit] Of course, I cannot imagine WHY this material would be chosen. It's not like plain bronze would be hard to do. Interesting photo!
[edit edit] Also, i'm not so sure about how fun a coin is that celebrates mob violence. Yay!